Angel García was probably the last person Amir Khan wanted to see in Los Angeles this week. But there he will be on Saturday night in the Memorial Sports Arena, the trainer who told him in July he had "never seen a Pakistani who could fight" and who, in all probability, will be leering across the ring at him in support of the British fighter's latest opponent, the unbeaten Californian Carlos Molina.

García was barely censured for that remark when he goaded Khan before his son, Danny, stopped him in four rounds in July to take his WBC and WBA light-welterweight belts. Nor was there much outcry when García Sr instigated a brawl with Zab Judah in New York this month, ahead of his son's first title defence in February.

Khan will cope. He has been around the business long enough. But it will be at least an unsettling distraction having Angel trying to meddle with his mind.

The one-time teenage Olympic silver medallist has long lost his innocence. It vanished in a blur of pain when García levelled him – with a left hook he should have seen coming the previous week – then overpowered him in a frenetic finish. Khan had so wanted to get back at Danny's father. But he was left with no ammunition. On Saturday he gets another chance for revenge, albeit through another opponent.

After leaving his trainer Freddie Roach that night in July under a cloud of ill will, Khan has tried to rebuild his career with the excellent Virgil Hunter, who mentors Andre Ward. There is widespread agreement Hunter is good – but so was Roach: the best, in fact, until a wretched run of defeats over the past year dented his reputation. It doesn't look good that Khan has left him, whatever the wisdom of it. It is hard to imagine Manny Pacquiao, also brutally felled – by Juan Manuel Márquez last weekend – abandoning the man to whom he owes so much.

That Roach and Khan have fallen out, perhaps irretrievably, is obvious. When the fighter tweeted that Roach's training skills had dissipated because of his Parkinson's disease, there was no way back. He subsequently tried to correct that view, but the trainer told him this week, through the Guardian, that he "really couldn't care" if Khan lost to Molina.

So now the ex-champion is adrift, yet still determined. He said he had tired of letting other people run his life, a fine sentiment up to the point where the powers of self-expression are dimmed by a slippage in credibility. He is fighting for the WBC's vacant "silver" light-welterweight title, no more than a fancy eliminator ahead of the real thing.

These details are minor to a fighter who turned 26 last week, while seeming more shopworn than Molina, who is nearly a year older but retains the glow of youth. Molina has had only 17 fights, all wins, to Khan's 29, three of which he has lost. It's far from a disastrous record, but he has to dispatch Molina in style to re-establish a career that has wobbled like his mouthguard lately.

How apt they should both box for Golden Boy Promotions. Oscar De La Hoya, whose smile could light up California (and once graced ads for milk), brings gilded promise to every show, as he did when gathering world titles at five weights, but he shed his own naivety some time ago.

The fight game is such a voracious beast and, whatever riches De La Hoya has made for and with Khan since the fighter left Bolton to establish his career in the United States with GBP, there is always a price to pay. For the deal-maker, there is the angst. For his fighter, there is the crushing pressure to deliver excitement, as Khan has done in nearly every one of his seven bouts since winning the WBA version of the light-welterweight title in 2009 with a carefully constructed points win over Andriy Kotelnik, a respected but not outstanding champion. Five of those engagements have been in America, but he has lost two on the spin and, whatever the trumpeting of his business partners, there is only so much excitement the networks can stand if the provider becomes damaged goods.

It is as if American boxing wants him, but is taunting him to justify their continued investment with a spectacular knockout – and that is not necessarily the right strategy for Khan, all of whose troubles have arrived in a rush of intemperance.

If Mr Hunter can persuade Khan of the efficacy of caution, he will have earned the fighter's trust and respect. If not, if the fighter walks into a knockout of his own construction, the game might be pretty much up.